To get back on topic....
I'd go with the VW Passat. While a Toyota diesel may be good, I never heard of them making a diesel engine until now. Audi's are nice cars but the extra expense for an Audi is not spent on durable parts, such as the engine or transmission. Audi's cost more for prestige, creature comforts (which are very expensive when they break after five years) and styling.
Out of curiosity, is a station wagon the European equivalent of a pickem' up truck? Also, I would not recommend an automatic transmission on a diesel unless you have driven the car for at least a week. I owned a MB 240D with an automatic and felt a manual transmission would have helped the car's performance. Owning the automatic transmission 240D discouraged me from considering any more diesel cars. I hear modern diesel drive trains are much better.
Regards,
Malta